1. Field of the Invention
This invention relates to a process for making 3-trichloromethyl-5-loweralkylamino-1,2,4-thiadiazole compounds.
2. Description of the Prior Art
3-Trichloromethyl-5-loweralkylamino-1,2,4-thiadiazole compounds are known as effective soil fungicides. See U.S. Pat. Nos. 3,260,588 and 3,260,725, both of which were issued to H. A. Schroeder on July 12, 1966. These compounds are also known as chemical intermediates in making N-3-trichloromethyl-1,2,4-thiadiazolyl (5)]-N,N'-di-loweralkylureas, which may be utilized as herbicides and nitrification inhibitors. See U.S. Pat. No. 3,822,280, issued to Hans Moser et al on July 2, 1974. Also see Chemical Abstracts, Vol. 76: 31239h and vol. 78: 70742c.
As noted in the above-cited Schroeder patents, these 3-trichloromethyl-5-loweralkylamino-1,2,4-thiadiazole compounds have been prepared by reacting trichloromethylacetamidine or its hydrochloride with trichloromethanesulfenyl chloride in the presence of alkali and an inert immiscible organic solvent to form 3-trichloromethyl-5-chloro-1,2,4-thiadiazole. This 5-chloro compound is then reacted with the appropriate loweralkylamine in benzene solvent in order to substitute a loweralkylamino group for the chloro group in the 5-position.
This prior art process for making these compounds, however, has certain commercially disadvantageous features. Particularly, this process requires more than one solvent. Thus, a solvent exchange step and an intermediate product isolation step are necessary. More importantly, the overall yields of the product are relatively low. Therefore, it would be advantageous if a new process for making these compounds was developed whereby only one solvent would be necessary and a higher overall yield of product was obtained.